/*
    This file is part of Cyclos (www.cyclos.org).
    A project of the Social Trade Organisation (www.socialtrade.org).

    Cyclos is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    Cyclos is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Cyclos; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */
package nl.strohalm.cyclos.utils.conversion;

import nl.strohalm.cyclos.entities.Entity;
import nl.strohalm.cyclos.utils.EntityHelper;

/**
 * Converter for entity references
 * @author luis
 */
public class ReferenceConverter<T extends Entity> implements Converter<T> {

    private static final long  serialVersionUID = 4903110311754130754L;
    private static IdConverter idConverter      = IdConverter.instance();

    public static <T extends Entity> ReferenceConverter<T> instance(final Class<T> entityType) {
        return new ReferenceConverter<T>(entityType);
    }

    private final Class<T> entityType;

    public ReferenceConverter(final Class<T> entityType) {
        this.entityType = entityType;
    }

    public String toString(final T object) {
        return object == null ? null : idConverter.toString(object.getId());
    }

    public T valueOf(final String string) {
        final Long id = idConverter.valueOf(string);
        return id == null ? null : EntityHelper.reference(entityType, id);
    }
}